# Configure RunAsUserName for Windows pods and containers LLMS index: [llms.txt](/llms.txt) ---

FEATURE STATE: Kubernetes v1.18 [stable]

This page shows how to use the `runAsUserName` setting for Pods and containers that will run on Windows nodes. This is roughly equivalent of the Linux-specific `runAsUser` setting, allowing you to run applications in a container as a different username than the default. ## Before you begin You need to have a Kubernetes cluster and the kubectl command-line tool must be configured to communicate with your cluster. The cluster is expected to have Windows worker nodes where pods with containers running Windows workloads will get scheduled. ## Set the Username for a Pod To specify the username with which to execute the Pod's container processes, include the `securityContext` field ([PodSecurityContext](/docs/reference/generated/kubernetes-api/v1.36/#podsecuritycontext-v1-core)) in the Pod specification, and within it, the `windowsOptions` ([WindowsSecurityContextOptions](/docs/reference/generated/kubernetes-api/v1.36/#windowssecuritycontextoptions-v1-core)) field containing the `runAsUserName` field. The Windows security context options that you specify for a Pod apply to all Containers and init Containers in the Pod. Here is a configuration file for a Windows Pod that has the `runAsUserName` field set:

    windows/run-as-username-pod.yaml
    
apiVersion: v1
kind: Pod
metadata:
  name: run-as-username-pod-demo
spec:
  securityContext:
    windowsOptions:
      runAsUserName: "ContainerUser"
  containers:
  - name: run-as-username-demo
    image: mcr.microsoft.com/windows/servercore:ltsc2019
    command: ["ping", "-t", "localhost"]
  nodeSelector:
    kubernetes.io/os: windows

Create the Pod: ```shell kubectl apply -f https://k8s.io/examples/windows/run-as-username-pod.yaml ``` Verify that the Pod's Container is running: ```shell kubectl get pod run-as-username-pod-demo ``` Get a shell to the running Container: ```shell kubectl exec -it run-as-username-pod-demo -- powershell ``` Check that the shell is running user the correct username: ```powershell echo $env:USERNAME ``` The output should be: ``` ContainerUser ``` ## Set the Username for a Container To specify the username with which to execute a Container's processes, include the `securityContext` field ([SecurityContext](/docs/reference/generated/kubernetes-api/v1.36/#securitycontext-v1-core)) in the Container manifest, and within it, the `windowsOptions` ([WindowsSecurityContextOptions](/docs/reference/generated/kubernetes-api/v1.36/#windowssecuritycontextoptions-v1-core)) field containing the `runAsUserName` field. The Windows security context options that you specify for a Container apply only to that individual Container, and they override the settings made at the Pod level. Here is the configuration file for a Pod that has one Container, and the `runAsUserName` field is set at the Pod level and the Container level:

    windows/run-as-username-container.yaml
    
apiVersion: v1
kind: Pod
metadata:
  name: run-as-username-container-demo
spec:
  securityContext:
    windowsOptions:
      runAsUserName: "ContainerUser"
  containers:
  - name: run-as-username-demo
    image: mcr.microsoft.com/windows/servercore:ltsc2019
    command: ["ping", "-t", "localhost"]
    securityContext:
        windowsOptions:
            runAsUserName: "ContainerAdministrator"
  nodeSelector:
    kubernetes.io/os: windows

Create the Pod: ```shell kubectl apply -f https://k8s.io/examples/windows/run-as-username-container.yaml ``` Verify that the Pod's Container is running: ```shell kubectl get pod run-as-username-container-demo ``` Get a shell to the running Container: ```shell kubectl exec -it run-as-username-container-demo -- powershell ``` Check that the shell is running user the correct username (the one set at the Container level): ```powershell echo $env:USERNAME ``` The output should be: ``` ContainerAdministrator ``` ## Windows Username limitations In order to use this feature, the value set in the `runAsUserName` field must be a valid username. It must have the following format: `DOMAIN\USER`, where `DOMAIN\` is optional. Windows user names are case insensitive. Additionally, there are some restrictions regarding the `DOMAIN` and `USER`: - The `runAsUserName` field cannot be empty, and it cannot contain control characters (ASCII values: `0x00-0x1F`, `0x7F`) - The `DOMAIN` must be either a NetBios name, or a DNS name, each with their own restrictions: - NetBios names: maximum 15 characters, cannot start with `.` (dot), and cannot contain the following characters: `\ / : * ? " < > |` - DNS names: maximum 255 characters, contains only alphanumeric characters, dots, and dashes, and it cannot start or end with a `.` (dot) or `-` (dash). - The `USER` must have at most 20 characters, it cannot contain *only* dots or spaces, and it cannot contain the following characters: `" / \ [ ] : ; | = , + * ? < > @`. Examples of acceptable values for the `runAsUserName` field: `ContainerAdministrator`, `ContainerUser`, `NT AUTHORITY\NETWORK SERVICE`, `NT AUTHORITY\LOCAL SERVICE`. For more information about these limitations, check [here](https://support.microsoft.com/en-us/help/909264/naming-conventions-in-active-directory-for-computers-domains-sites-and) and [here](https://docs.microsoft.com/en-us/powershell/module/microsoft.powershell.localaccounts/new-localuser?view=powershell-5.1). ## What's next * [Guide for scheduling Windows containers in Kubernetes](/docs/concepts/windows/user-guide/) * [Managing Workload Identity with Group Managed Service Accounts (GMSA)](/docs/concepts/windows/user-guide/#managing-workload-identity-with-group-managed-service-accounts) * [Configure GMSA for Windows pods and containers](/docs/tasks/configure-pod-container/configure-gmsa/)